What started as a battle between dominant starting pitchers hinged on a late-inning at-bat between Pedro Alvarez and Kevin Siegrist.

Alvarez delivered and the Pirates' 5-3 win against the St. Louis Cardinals at PNC Park Sunday gave them a 2-1 lead in the National League Division Series.

The Cardinals face elimination in Game 4 which takes place Monday at PNC Park. They will send rookie Michael Wacha to the mound opposite Charlie Morton.

The Pirates held a 3-2 lead until the eighth inning when Carlos Beltran homered to right-center field off Mark Melancon and rendered PNC Park momentarily silent. Beltran's 16th career postseason homer moved him past Babe Ruth on the all-time list. He is now one behind Jim Thome.

Melancon allowed one home run in 71 regular-season innings on April 14 against the Cincinnati Reds.Andrew McCutchen doubled to start the bottom of the eighth but tried to take third base on Justin Morneau's ground ball to the left side of the infield and made the first out of the inning at third base.

Alvarez singled to right field scoring Harrison and the Pirates took a lead. Russell Martin's RBI single added an insurance run.

Francisco Liriano allowed two runs in six innings in his start striking out five.

St. Louis scored only two runs in 24 innings against Liriano during his three starts against the Cardinals this season. He struck out 20 and held the Cardinals to a .127 average without a home run. Liriano also had a 1.47 ERA and 72 strikeouts in 732/3 innings at PNC Park this season not including his seven-inning one-run outing against the Cincinnati Reds in Tuesday's wild-card game.

During three starts against the Pirates each six inning in length Cardinals starter Joe Kelly allowed a combined two runs. The Pirates equaled that run total in Sunday's first inning.

Kelly issued a two-out walk to McCutchen usually not a harbinger of positive developments. Morneau's grounder deflected off Kelly for an infield single putting men on first and second but Pete Kozma's late throw in an attempt to get Morneau at first went wide and moved both runners into scoring position.